Yes you can find WI-Fi all over and yes Most places secure it Thank Hackers and "War-Drivers" who either steal bandwidth or .. Everything of importance on your computer (including your ID).
But Libraries often will either let you use it, or let you use it for a small fee. McDonalds, Burger King, Lowes, home Depot, Wal*Mart, Subway, Ruby Tuesdays (Sucks near me) Denny's (Blazing bandwith Batman (The one nearest me is fantastic, other restaurants. Staples, Rest areas (some of them) Campgrounds and so many other places I can not list them all now have Free Wi-Fi.. MOST (But not all) use special routers that DIS-allow peer to peer connections within the network (Makes it harder, but not impossible, for hackers) some....
Well, I recall one campground not all that long ago (They have since upgraded) I'd get over to the Family Center, which is where the Wi-Fi Worked, long about 7:30/8am and log in.. Get my IP assignment and all was good.. long about 9:30 folks were "I can't connect".. NOTE: the SSID was LINKSYS back then I kid you not.
Well, I'd set 'em up with a Static IP and instructions on how to switch back to Dynamic, and they were good..
Finally I decided to "hack".. I typed in the URL of the router, it responded (no surprise) and ask for a user name and password.. I entered the DEFAULT user name and password, and it said "Welcome" I checked and found it was set to hand out only 50 addresses.. Changed it to 100 and logged out.
Next day I'm helping Susie connect (Same issue) I explained that when they set it up a few folks used laptops but today we have Laptops, Cell phones, PDA, Tablets and even the park's game machine... Logged back in and displayed the DCHP list.. Including one entry "Susie's I-Phone".. That's when I found out her name.. Her phone.
With this type of router. Well,, Easy to connect to your system and download, and since you are WITHIN the LAN (local net) the hardware firewall in the router won't help.
Today you have to enter a password, then you need a user name and password, and it's "Gated" so you can't peer to peer. Which is good.